The document says "Multiple checkpoint nodes may be specified in thecluster configuration file".

Can some one clarify me that why we really need to run multiple checkpointnodes anyway? Is it possible that while checkpoint node A is doingcheckpoint, and check point node B kicks in and does another checkpoint?

> Hi all,>> The document says "Multiple checkpoint nodes may be specified in the> cluster configuration file".>> Can some one clarify me that why we really need to run multiple checkpoint> nodes anyway? Is it possible that while checkpoint node A is doing> checkpoint, and check point node B kicks in and does another checkpoint?>> Thanks,> Thanh>

> more checkpoint nodes means more backup of the metadata :)>> *Thanks & Regards *>> ∞> Shashwat Shriparv>>>> On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>> Hi all,>>>> The document says "Multiple checkpoint nodes may be specified in the>> cluster configuration file".>>>> Can some one clarify me that why we really need to run multiple>> checkpoint nodes anyway? Is it possible that while checkpoint node A is>> doing checkpoint, and check point node B kicks in and does another>> checkpoint?>>>> Thanks,>> Thanh>>>>

It would be important to point the document (which I believe ishttp://hadoop.apache.org/docs/stable/hdfs_user_guide.html) and the versionof Hadoop you are interested in. At one time, the documentation wasmisleading. The 1.x version didn't have checkpoint/backup nodes only thesecondary namenode. I don't believe it has changed but I might be wrong (orthe documentation still hasn't been fixed). The 2.x version will havenamenode HA which will be the final solution.

> It would be important to point the document (which I believe is> http://hadoop.apache.org/docs/stable/hdfs_user_guide.html) and the> version of Hadoop you are interested in. At one time, the documentation was> misleading. The 1.x version didn't have checkpoint/backup nodes only the> secondary namenode. I don't believe it has changed but I might be wrong (or> the documentation still hasn't been fixed). The 2.x version will have> namenode HA which will be the final solution.>> Regards>> Bertrand>>> On Thu, Apr 18, 2013 at 7:20 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>> so reliability (to prevent metadata loss) is the main motivation for>> multiple checkpoint nodes?>>>> Does anybody use multiple checkpoint nodes in real life?>>>> Thanks>>>>>> On Thu, Apr 18, 2013 at 12:07 PM, shashwat shriparv <>> [EMAIL PROTECTED]> wrote:>>>>> more checkpoint nodes means more backup of the metadata :)>>>>>> *Thanks & Regards *>>>>>> ∞>>> Shashwat Shriparv>>>>>>>>>>>> On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>>>>>> Hi all,>>>>>>>> The document says "Multiple checkpoint nodes may be specified in the>>>> cluster configuration file".>>>>>>>> Can some one clarify me that why we really need to run multiple>>>> checkpoint nodes anyway? Is it possible that while checkpoint node A is>>>> doing checkpoint, and check point node B kicks in and does another>>>> checkpoint?>>>>>>>> Thanks,>>>> Thanh>>>>>>>>>>>>>>> --> Bertrand Dechoux>

> It would be important to point the document (which I believe is> http://hadoop.apache.org/docs/stable/hdfs_user_guide.html) and the> version of Hadoop you are interested in. At one time, the documentation was> misleading. The 1.x version didn't have checkpoint/backup nodes only the> secondary namenode. I don't believe it has changed but I might be wrong (or> the documentation still hasn't been fixed). The 2.x version will have> namenode HA which will be the final solution.>> Regards>> Bertrand>>> On Thu, Apr 18, 2013 at 7:20 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>> so reliability (to prevent metadata loss) is the main motivation for>> multiple checkpoint nodes?>>>> Does anybody use multiple checkpoint nodes in real life?>>>> Thanks>>>>>> On Thu, Apr 18, 2013 at 12:07 PM, shashwat shriparv <>> [EMAIL PROTECTED]> wrote:>>>>> more checkpoint nodes means more backup of the metadata :)>>>>>> *Thanks & Regards *>>>>>> ∞>>> Shashwat Shriparv>>>>>>>>>>>> On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>>>>>> Hi all,>>>>>>>> The document says "Multiple checkpoint nodes may be specified in the>>>> cluster configuration file".>>>>>>>> Can some one clarify me that why we really need to run multiple>>>> checkpoint nodes anyway? Is it possible that while checkpoint node A is>>>> doing checkpoint, and check point node B kicks in and does another>>>> checkpoint?>>>>>>>> Thanks,>>>> Thanh>>>>>>>>>>>>>>> --> Bertrand Dechoux>

Yeah, I read the thread that Checkpoint/BackupNode may be get deprecated.SNN is a way to go then.

I just wonder if we use multiple CheckpointNodes, we might run into thesituation where while a checkpoint is on-going, but the firstCheckpointNode is slow, then the second checkpointNode kicks in, justwonder what would happen.On Thu, Apr 18, 2013 at 3:07 PM, Mohammad Tariq <[EMAIL PROTECTED]> wrote:

> Hello Thanh,>> Just to keep you updated, checkpoint node might get depricated. So,> it's always better to use secondary namenode. More on this could be found> here :> https://issues.apache.org/jira/browse/HDFS-2397> https://issues.apache.org/jira/browse/HDFS-4114>> Warm Regards,> Tariq> https://mtariq.jux.com/> cloudfront.blogspot.com>>> On Fri, Apr 19, 2013 at 1:15 AM, Bertrand Dechoux <[EMAIL PROTECTED]>wrote:>>> It would be important to point the document (which I believe is>> http://hadoop.apache.org/docs/stable/hdfs_user_guide.html) and the>> version of Hadoop you are interested in. At one time, the documentation was>> misleading. The 1.x version didn't have checkpoint/backup nodes only the>> secondary namenode. I don't believe it has changed but I might be wrong (or>> the documentation still hasn't been fixed). The 2.x version will have>> namenode HA which will be the final solution.>>>> Regards>>>> Bertrand>>>>>> On Thu, Apr 18, 2013 at 7:20 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>>>> so reliability (to prevent metadata loss) is the main motivation for>>> multiple checkpoint nodes?>>>>>> Does anybody use multiple checkpoint nodes in real life?>>>>>> Thanks>>>>>>>>> On Thu, Apr 18, 2013 at 12:07 PM, shashwat shriparv <>>> [EMAIL PROTECTED]> wrote:>>>>>>> more checkpoint nodes means more backup of the metadata :)>>>>>>>> *Thanks & Regards *>>>>>>>> ∞>>>> Shashwat Shriparv>>>>>>>>>>>>>>>> On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do <[EMAIL PROTECTED]> wrote:>>>>>>>>> Hi all,>>>>>>>>>> The document says "Multiple checkpoint nodes may be specified in the>>>>> cluster configuration file".>>>>>>>>>> Can some one clarify me that why we really need to run multiple>>>>> checkpoint nodes anyway? Is it possible that while checkpoint node A is>>>>> doing checkpoint, and check point node B kicks in and does another>>>>> checkpoint?>>>>>>>>>> Thanks,>>>>> Thanh>>>>>>>>>>>>>>>>>>>>>> -->> Bertrand Dechoux>>>>

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